Square tie wire for securing rebar

ABSTRACT

Tie wire with a square cross section is provided which has a 30% increase in tensile strength and at least a 100% increase in surface contact with rebar which it is used to secure. The generally square configuration includes four convex portions at the corners, each pair of convex portions being interconnected by a concave portion. The concave portions may achieve an even larger increase in surface contact as they contact the surface of the rebar.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] The present invention is directed to a square tie wire for securing rebar at crossover points in concrete construction prior to pouring concrete and during curing to prevent shifting of the rebar.

[0002] Concrete is used for many applications including roads, bridges, floors and walls of commercial buildings, among others. While concrete has excellent strength in compression, it has considerably less strength in tension. Accordingly, steel reinforcement elements known as rebar is frequently used to impart additional tensile strength to the resultant structure. Tie wire is used to secure two or more lengths of rebar at a junction to prevent the weight of the poured concrete from repositioning the rebar from the desired locations.

[0003] Tie wire used in securing rebar in concrete molds conventionally has a round cross section. Such wire has only single point contact (at the point of tangency of its surface) with the rebar and, therefore, can easily slip allowing shifting of the rebar prior to or during the pouring of the concrete. In addition, the round wire has limited tensile strength which can result in breaking of the wire as it is subjected to the forces associated with pouring or working the liquid concrete.

[0004] The present invention proposes to provide a generally square cross-sectioned tie wire to increase surface contact between said tie wire and the rebar for enhanced securement. The tie wire has four convex portions, one convex portion at each corner, adjacent corner convex portions forming a pair of convex corner portions, each of the pair of convex corner portions being interconnected by an intermediate concave portion, said concave portions providing enhanced contact between the tie wire and the surface discontinuities of the rebar. The tie wire of the present invention has increased tensile strength resulting from its increased density. The tensile strength of the square cross-section wire will be on the order of 30% greater than that of the standard round wire.

[0005] Other features, advantages and characteristics of the present invention will become apparent after a reading of the following specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The preferred embodiment(s) of the present invention is/are set forth in the drawings, like items bearing like reference numerals and in which

[0007]FIG. 1 is cross-sectional end view of a first embodiment of the tie wire of the present invention; and

[0008]FIG. 2 is enlarged schematic side view of a rebar connection employing the wire of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(s)

[0009] A first embodiment of the square tie wire of the present invention is depicted in FIGS. 1 and 2 generally at 20. The square tire wire 20 will actually have four convex portions 22, one at each corner. Each pair of convex corner portions 22 is interconnected by an intermediate concave portion 24. The square tie wire 20 of the present invention will, gauge for gauge, will be 30% stronger than its conventional round counterpart as a result of the increase in volume of material. This increase strength will be achieved with little or no loss of flexibility of the wire. Further, whereas, the round tie wire had only a single point contact with the rebar at the point where the tangency of the wire surface engages the rebar, the square wire 20 of the present invention has at least twice the surface contact (100% increase) and may well have considerably more if the concave portion 24 of wire 20 engages the rounded surface of the rebar 11, 13 or a reinforcement protrusion 15 on the rebar 11, 13.

[0010]FIG. 2 depicts an intersection 17 of a first length of rebar 11 and a crossing length of rebar 13. A length of wire 20 is twisted about the intersection 20 to secure the members in place. The application could involve a road, a bridge, or a floor or wall of a commercial building, or any such application where concrete is to be poured for structural purposes. Square tie wire 20 of the present invention will have better holding strength because of its increased density and surface contact with the rebar. Tie wire 20 may optionally be coated with any surface coating 26 known in the trade such as polyurethane, paint or other surface treatments.

[0011] Various changes, alternatives and modifications will become apparent after a reading of the foregoing specification. It is intended that all such changes, alternatives and modifications as fall within the scope of the appended claims be considered part of the present invention. 

I claim:
 1. A tie wire for use in securing rebar at crossover points in concrete construction, the rebar having surface discontinuities, said tie wire comprising a strand of wire having a generally square cross section to increase surface contact between said tie wire and the rebar for enhanced securement.
 2. The tie wire of claim 1 wherein said tie wire has four convex portions, one said convex portion at each corner, adjacent corner convex portions forming a pair of convex corner portions, each said pair of convex corner portions being interconnected by an intermediate concave portion, said concave portions providing enhanced contact between said tie wire and the surface discontinuities of the rebar.
 3. The tie wire of claim 1 wherein said tie wire has 30% higher tensile strength than a similar gauge round tie wire resulting from its increased density.
 4. The tie wire of claim 1 further comprising a coating on a surface portion of said tie wire. 